If this is new territory for you, you're in for an education. One that by all rights you shouldn't have to go through unless you wanted to become a mechanic. But the way it works today this is your most direct path to a solution, otherwise you're bound to hoping it happens while a mechanic is watching it.
In a perfect world vehicle computers would not only log and retain error codes but also the operating conditions that caused them. Sometimes even if they do, they're obscured within other data or it's readable only though specialized diagnostic equipment. The OBD readers out there today only go so far but some data is better than no data. So for intermittent problems like these where it doesn't happen for the mechanic, having some of the diagnostic data you gather yourself can be a big step to resolving the problem whether you take it somewhere or fix it yourself.
In this case in particular, I think just because it's not an emissions related issue the code set may not be stored. Which could be manufacturer or even model specific, I've seen it reported both ways. In any event, pulling codes as soon as it happens makes sure you get as much diagnostic info as possible.
I use an OBDLink MX, about $50. It seems to work just fine with drivetrain data. I use that with Torque on an android tablet, as a tablet screen is easier to see while driving than squinting at a phone screen. I can monitor all the usual engine parameters as well as transmission slip, shift speeds and temperature. Watching this data in real time may reveal the condition or circumstance that causes the computer to resort to limp mode. The Torque app has the ability to store operating data as it runs, so you can go back and review things at the moment the problem occurs.
Rest assured that whatever is causing this to happen will not go away on its own. Something like a fried clutch or bad pump will eventually lead to complete transmission failure and probably not at a convenient place or time. It could be something simple like low fluid or a sticking shift solenoid. If it's engine related you can see the fuel pressure, timing, fuel mixture and throttle. There's probably a dozen or more different things that can trigger limp mode. So it's worth the time to set yourself up to be able to work with OBD data and know what's going on. Sucks that in this day and age with computers and processors in just about every thing we touch, we're bound to hooking our phones up to the vehicle and deciphering obscure codes and data to figure out what's wrong. But that's better than being broken down on the side of the road and wondering why it won't go.
Mark B.
Albuquerque, NM
